pro&con of 16cm,14cm,12cm

[Ewright]

I'm right ready to make my first power up grade by changing the exhaust housing. Most people here seem to run the 16cm non-wastegated. And I read that as you step down in cm you can expect a 2-3lb boost gain. What are the draw backs for going down in size? Possible loss of top end power? If 16cm with it's boost gain is good, why wouldn't 14or12cm be even better? Also, where can I get my hands on the old smokey mount, how much can I expect to pay and does it flow more air than a K&N w/ a drilled box? Thanks as always. ERIC

 

[Withers]

You can get a hold of Old Smokey through private message on TDR or e-mail him directly, Just go through the members list or readers rigs, he has the mounts listed there. As far as the housings the smaller you go the higher your EGT's will go, your forcing huge amounts of are through a smaller housing, causing higher temps, which makes it hard to haul heavy loads for any duration, the bigger the housing the cooler your EGT's will be, if you do no hauling the 14cm housing will work ok, the 16cm housing is a good all around size, not to big , not to small. As far as boost, yes, the smaller the housing the more boost you will build, if your running a 21cm housing and go down to a 12cm you should notice a huge difference, way faster spool up, but you will lose at top end, I think , I still have the stock 18cm, I might go to a 16cm when I get a new turbo, most of the guy's know a lot more then me, and will be chiming in shortly.

 

[Matt S]

I've had both the 16 and the 12 on my truck. I'm currently running the 12 as I like the way the boost builds. Much faster when driving around town or on a small island in my case. If you mostly drive on the wide open high way, then the 12 might be too small as you will be running with boost at high way speeds. The 16 was more smokey for me and I didn't care for the lag. There is about a 5 hp difference on the top end with the 16 making more but the low end seems like the 12 is making more. It all depends on the way you use the truck. If you need the quick speed to get out in traffic, go with the 12. If you can live with some lag, go with the 16. I've towed across the country with the 12 and liked it. The way my truck is set up, I didn't have any EGT problems with zero downshifts required. You can also get a 12 to try from a 2nd Gen for usually the cost of shipping to try out.



Matt

 

[Ewright]

2002 unit

Can I use a whole unit (wastegated turbo and exhaust housing) from a 2002 5spd truck? Would I need to modifie anything? Like the down pipe? Eric

 

[dpuckett]

Re: 2002 unit

Originally posted by Ewright

Can I use a whole unit (wastegated turbo and exhaust housing) from a 2002 5spd truck? Would I need to modifie anything? Like the down pipe? Eric

Eric,

First if you go with a 12 or 14, you will need to shorten the horizontal part of the downpipe about 1. 5" to accomodate the WG housing. A housing from an 02 will work provided it is a HX35 and not a HY35. But you will have to get more into exhaust mods- somewhere after the introduction of the 24v motor, they changed the way the housing bolts to the exhaust pipe.



Now, for housing selection:

If you have a 5 speed, 4. 10s, and do a lot of heavy towing (15K+ GCVW), then a 16 would be best, or maybe even an 18, depending on if the 18 is ported and how many RPMs you turn.



If you have an auto with 3. 54s, and do little or no towing, then the 12 may be your best bet. QUick bottom end spooling, higher cruise boost (more air equals lower EGTs), and you wont turn enough RPMs for exhaust restriction to be a big factor, unless you drag race or run 80+.



I have a 12 on my PDR HX35, and like it for local 55 mph driving empty. When I move back home, I'll either get a 16 or an overdrive. Boost builds up FAST with a 12, and you have pretty good flow till about 2400 RPM or 25 psi boost. I think after that, you run into drive pressure vs bost pressure differences, and it becomes less efficient. With stock injectors, and some pump tweaks, I can hit 34 psi empty up a hill, and never see the red zone pre turbo- 1225 is about max. I didnt notice much cruise difference in boost or EGT- about 5-8 psi/ 600-700 deg either one. MPGs may have dropped a hair with my heavy-ish foot, but it could also be that I am driving shorter distances here vs the prairie, not to mention I use the extra bottom end every time I pull into traffic.



Now if you have an auto and 4. 10s or a 5 speed with 3. 54s, it would be a toss up between a 14 (WG or NWG) and a 16 NWG. For even light towing, I'd like to have the higher flow of the 16.



I am by no means an expert in this field; just what I've learned here, combined with personal experience.



Daniel

 

[Ewright]

Truck Specifics

I've got a auto w/ 3. 54's, do light towing (Hay,lumber,compost,etc. ) do most of my driving around town and when on the highway like to run about 75 or 80mph.

W/ the 02' can I use the turbo also and is there a benefit to having the wastegate?

 

[BushWakr - RIP]

Hey how about if someone does a factual post on the effects of boost pressures, drive pressure, EGT's, and application issues surrounding turbo exhaust housings... ... .



Formula,,,, you out there bud... ???? someone????



bob.

 

[Ewright]

2nd Gen housing Price?

Anybody know how much a 2nd gen 12cm exhaust housing is worth?

 

[Matt S]

I'm not sure if it was in a TDR article or a post but someone had a comparison on it.



A 2nd Gen housing can be had for the cost of shipping. You just need to look around.

 

[rkubicki]

I put a whole HX35 turbo (12w housing and all) right on my truck... If you can find a good deal for the whole turbo, it beats trying to pound off the stock nozzle - they're usually seized on pretty good... I think my unit came off a stock '95 model.



Bob (BushWakr) came up with a good idea to prevent the need for cutting/shortening the downpipe... With the downpipe disconnected at the turbo, apply a backward pulling force on the whole exhaust - I used a floor jack and raised up my muffler... The higher I raised, the more clearence I got. . After the turbo is in, slowly lower the exhaust onto the turbo's outlet... I have been running this setup for more than half a year now without any trouble.



I really like the 12cm housing... It puts the torque down low, it helps eliminate tip-in smoke, it sounds really cool, and with a stock pump and injectors it doesn't affect EGTs much (I tested this yesterday pulling 7000lbs. up 7% grades for 2+ miles in W. Va. )



Rob

 

[formula]

Originally posted by BushWakr

Hey how about if someone does a factual post on the effects of boost pressures, drive pressure, EGT's, and application issues surrounding turbo exhaust housings... ... .



Formula,,,, you out there bud... ???? someone????



bob.

You cookin up porkchops again, Bob? :-laf



I've been thinking of tapping the boss on the front side of the exhaust flange to take some drive pressure readings. When I do, I will definitely post the results.



Ewright,

If you don't plan on adding much more fueling, then the 12cm will be just fine. But, if you're like most of us, then that will not be enough for very long. In which case the 12cm will be too restrictive. The easiest swap to do is to put in a 16cm non wastegated housing. No mods to the exhaust pipe are needed.



Cheers,

Sean

 

[Ewright]

Road taken

So here's where I went: 16cm PDR housing (looking towards the future and more POWER). Also ordered a smokey mount, BHAF, and Isspro gauges. The future looks smokey. Thanks for all your input. Eric

 

[Mgrant]

I sure like my 12cm! Just got done towing my gooseneck and I had 10mph worth of more power available on the same hills than I had with the 16cm with no EGT problems at all. I agree that the 16cm is the best for freeing up the high RPM horsepower for highway drags, but when towing heavy loads up monsterous grades, the 16cm had my EGTs too high near the peak torque RPM the CTD and the smoke was too much for my comfort. For my kind of towing, heavy fueling and a 16cm housing would spell certain disaster with the limited cooling of the 1st gen radiator and the EGTs would be beyond the red zone. I believe with moderate fueling with PW injectors and a 12cm housing is the best all around set-up for towing heavy loads in steep terrain. Gear changes are easier, more power is available at lower RPMs, turbo lag is non existant, and no belching smoke. As an added note, my engine oil stays cleaner for twice the miles than it did with the 16cm. BTW, stoplight tire roasting is all too easy with the 12cm, but I try to refrain from letting the devil out of the Ram with the cost of Toyo tires these days



Mike